updated 11:50 am EDT, Mon May 5, 2014

Group working toward $10 million goal

Apple has joined a list of companies that have agreed to donate $500,000 apiece to a San Francisco anti-poverty charity, SF Gives, two sources tell Fortune. In all about 15 companies have signed up for the initiative so far, including Google, Zynga, and LinkedIn. SF Gives was started by Salesforce CEO Marc Benioff and Tipping Point CEO Daneil Lurie; the goal is to have 20 business sign up by Wednesday, leading to a total contribution of $10 million. That money in turn will be donated to local charitable programs.

At least 10 companies have declined to make donations. Lurie notes that while some of them said they're already contributing in their own ways, others aren't generating revenue yet and don't want to give away investors' cash. Another group of businesses refused on ideological grounds, claiming that only individuals should be doing philanthropy, not businesses.

Apple has become increasingly charitable since the transition from Steve Jobs to current CEO Tim Cook; Jobs was infamously conservative about contributions, although they did occur under his watch. Businesses like Apple and Google may have special interest in improving their reputation in San Francisco, since the salaries they pay have contributed to gentrification, forcing out people with average or below-average wages. Google in particular has been protested for running private shuttles in the city, something controversial not just because of the gentrifying effect but because of the company's use of public bus stops. In February it agreed to donate $6.8 million toward free public transit for poor children, but only for two years. Some activists argue that Google owes much more in fines for using the public stops.